Page 29 - SuDS Design & Evaluation Guide-Newham V4 Spreads

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In most locations the water table is likely to studies and LLFA detailed requirements can LLFA, in its Statutory Consultee function, SuDS, nor LCY’s objection accepted without
Local SuDS requirements
be found at depths of less than 3 metres. be found on Newham webpage as below: requires that greenfield runoff calculations site specific evidences and mitigation
Ground water source protection zones are LB Newham Flooding Webpage should be performed using the IH124 method requirements provided to be evaluated by
found in the northern part of the borough. as supported by the HR Wallingford UK SuDS Newham Local Planning Authority.
Flood Risk and Sustainable Drainage: online greenfield runoff rate estimation tool.

Requirements and Guidance for Planning Under the same concern greenfield London City Airport guidance on biodiversity
Application calculations should adopt the default and safeguarding
Newham Local Plan parameters (e.g. soil type) as provided by the Pre-planning advice Local SuDS requirements
UK SuDS tool as characteristic of the Newham LLFA can provide pre-application
Newham LLFA drainage pro-forma
application site location. advice for developments as part of a pre-
Planning Application Requirements
Newham LLFA will not object to greenfield application consultation agreement with
Highlights of main requirements: runoff calculations based on Flood Newham Local Planning Authority.

Fig.5 Newham’s main made ground • All major development is required to Estimation Handbook (FEH) methodology, Please note that a fee specific to LLFA
(grey/grey hatched) and source restrict post development runoff to provided that the results are demonstrated to services is required:
protection zones (shades of pink)
greenfield runoff rates unless it can be be largely consistent with IH124 methodology Pre-Application Advice Guidance Note &
The combination of these factors may limit demonstrated that site conditions prohibit output from UK SuDS online tool and Charging Schedule
potential for infiltration drainage. However, the ability to do so. representative of the application site in a
given the high variability in ground conditions • All development must restrict runoff pre-development greenfield condition. LLFA advice can include providing specific
found across the borough, it is recommended discharge within or to Critical Drainage Newham LLFA does not accept the following information on local flood risk, review of
that developers carry out thorough ground Areas (CDA) to greenfield rates or below. approaches: information provided by developer relevant
investigations to establish the potential for N.B. there are 15 CDAs in Newham. • urban soil types for Greenfield runoff to the SuDS design and making
recommendations on compliance with local
23 infiltration. It should be noted that none of • Discharge to tidal water (i.e. River estimation and national policies. 24
the above prevents use of SuDS within a
Thames, Lea and Roding) will need to • applying urban catchment parameters to
development, if integrated into the design at runoff estimation The above could be arranged by contacting
an early stage. In any case, above ground no take account of the effect of “tide Newham Planning Authority development.
locking”, storm surge or submergence of Local LPA and Stakeholder Engagement
infiltration SuDS measures can still be used in control@newham.gov.uk
areas of contaminated ground provided that the outfall, in order to prevent flooding. In addition to LLFA the Environment Agency
An appropriate allowance in terms of Adoption of SuDS
barriers to contain contaminants, such as and Thames Water must be consulted with
impermeable liners, are used to protect onsite storage should be built into the concern of flood risk, discharge consents, Newham will not adopt SuDS unless
drainage strategy. undertaken by LB of Newham on council
groundwater. building in proximity to flood defences
• Discharge to tidal water may not be structures and watercourses. owned land. Applicants should therefore put
Local SuDS specific requirements restricted to greenfield provided scour/ London City Airport (LCY): Under concern of in place arrangements for maintenance and
erosion would not result, however a level end of life replacement of SuDS. Details must
Newham has developed a number of of attenuation will be expected - normally risk management (i.e. bird strike) LCY may be provided to the LLFA to add to its asset
documents in connection with local flood risk object to development proposal deemed register. There are other Risk Management
assessment and management. Main a 1 in 30 attenuation - to create SuDS potentially to increase of bird presence in the Authorities, such as Thames Water or TFL
features that provide additional benefits.
requirements applicable to major airport safeguard area. Whilst this concern that may be willing to consider adoption of
development are fully embodied in Newham’s Application of Greenfield Runoff Rates should be heeded and early consultation with SuDS. Early engagement with the relevant
local policy (Newham Local Plan 2018). To enable consistency of assessment City Airport is advised, LCY’s general concern party is critical to ensure their requirements

Links to relevant Newham policy, flood risk between planning applications, Newham should never be used to scope out can be achieved.
requirement of green infrastructures, such

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